1. Field of the Invention
The present invention relates generally to computer networks, and more particularly but not exclusively to methods and systems for communicating in a peer-to-peer network.
2. Description of the Background Art
Peer-to-peer (“P2P”) is a type of computer network that allows one computer to directly communicate with another computer with little or no assistance from a central server. P2P networks are widely employed in both personal and business environments to transfer data, such as files for music, word processing, spreadsheet, video, and so on. Although P2P networks may have varying implementation details, most P2P networks allow files to be transferred directly from one computer to another. P2P networks may be implemented on the Internet. On the Internet, a P2P network typically requires the services of a P2P server to facilitate the establishment of direct communication channels between computers belonging to the P2P network.
FIG. 1 shows a schematic diagram of a conventional P2P network 140. P2P network 140, which may be on the Internet, includes a P2P server 120 and a plurality of peer nodes 110 (i.e., 110-1, 110-2, . . . ). A peer node 110 may communicate with P2P server 120 over a communication channel 141 (i.e., 141-1, 141-2) and with another peer node 110 over a communication channel 143.
A peer node 110 may be a personal computer, for example. A peer node 110 may include a P2P module 112(112-1, 112-2, . . . ) and one or more files 113(113-1, 113-2, . . . ). A P2P module 112 may comprise computer-readable program code (i.e., software) for communicating with a P2P server 120 and for directly communicating with another peer node 110.
A P2P server 120 may be a computer server that has information on the whereabouts of peer nodes 110 that belong to the P2P network. Peer nodes 110 that belong to the P2P network are also referred to as members of the “P2P community.” A P2P server 120 may include a presence map 122 and a P2P manager 123. A presence map 122 may be a table or data structure containing presence information of peer nodes 110 belonging to the P2P network. Presence information may include the location information of a peer node 110, such as its IP address and port number. A P2P manager 123 may comprise computer-readable program code for providing a registrar function and a proxy function. The registrar function of P2P manager 123 allows peer nodes 110 to register its address with P2P server 120. For example, peer node 110-1 may register with P2P server 120 by providing its address. In P2P server 120, in response to the registration, P2P manager 123 may enter the address of peer node 110-1 in presence map 122. The proxy function of P2P manager 123 is employed to proxy session information between peer nodes 110. For example, invitations and acknowledgements for direct data transfers between peer nodes may be transmitted through P2P server 120 using the proxy function of P2P manager 123. Once communication has been established between peer nodes 110, the peer nodes 110 may directly exchange data without going through P2P server 120.
One problem with P2P networks is that direct data exchange between two peer nodes may facilitate the transfer of computer viruses. Unless every peer node in the P2P network has up-to-date antivirus software, one infected peer node may spread a virus to other peer nodes. Another problem with P2P networks is the lack of control on the data being transferred between nodes. While this might not be a concern among personal users, some businesses or organizations may have requirements on the kind of data that may be exchanged over the P2P network.